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References: <20220217120856.2910-1-zajec5@gmail.com>
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From:   Rob Herring <robh+dt@kernel.org>
Date:   Thu, 17 Feb 2022 15:15:54 -0600
Message-ID: <CAL_JsqJjZRJCHDUK7Pia0ontdAGgvqgfPQgpu6A+UH+qovEJOQ@mail.gmail.com>
Subject: Re: [PATCH RFC *RFC*] dt-bindings: add U-Boot chosen for environment
 data phandle
To:     =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= <zajec5@gmail.com>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        devicetree@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Tom Rini <trini@konsulko.com>,
        Ricardo Salveti <ricardo@foundries.io>,
        Michal Simek <michal.simek@xilinx.com>,
        Jorge Ramirez-Ortiz <jorge@foundries.io>,
        U-Boot Mailing List <u-boot@lists.denx.de>,
        =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= <rafal@milecki.pl>
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On Thu, Feb 17, 2022 at 6:09 AM Rafa=C5=82 Mi=C5=82ecki <zajec5@gmail.com> =
wrote:
>
> From: Rafa=C5=82 Mi=C5=82ecki <rafal@milecki.pl>
>
> This is RFC and request for a help & discussion.
>
> While reviewing patch for U-Boot env binding it has been mentioned that:
>
> 1. /Processing/ whole DT in U-Boot may be too much work
>    Handling flash devices, partitions, their formats & NVMEM may require
>    too many U-Boot drivers involved.
>
> 2. It'd be nice to have env data storage devices pointed in chosen
>
> I wrote this hacky PATCH to give a rough idea how it could look like.
>
> Please review this and let me know:
> 1. If solution with chosen + phandles is acceptable
> 2. How to properly name .yaml file
> 3. Where it put it
>
> Signed-off-by: Rafa=C5=82 Mi=C5=82ecki <rafal@milecki.pl>
> ---
>  .../devicetree/bindings/u-boot,chosen.yaml    | 39 +++++++++++++++++++
>  1 file changed, 39 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/u-boot,chosen.yaml
>
> diff --git a/Documentation/devicetree/bindings/u-boot,chosen.yaml b/Docum=
entation/devicetree/bindings/u-boot,chosen.yaml
> new file mode 100644
> index 000000000000..8369da91193d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/u-boot,chosen.yaml
> @@ -0,0 +1,39 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/u-boot,chosen.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: U-Boot setup
> +
> +maintainers:
> +  - Rafa=C5=82 Mi=C5=82ecki <rafal@milecki.pl>
> +
> +properties:
> +  u-boot,env:
> +    $ref: /schemas/types.yaml#/definitions/phandle-array
> +    description: |
> +      A list of storage volumes containing U-Boot environment data.
> +
> +      Env data can be stored on various kinds of storage devices, e.g.:
> +      1. Raw flash partition
> +      2. UBI volume
> +
> +additionalProperties: true
> +
> +examples:
> +  - |
> +    chosen {
> +        u-boot,env =3D <&env>;

You should look at the u-boot config support:

https://github.com/devicetree-org/dt-schema/commit/0986f729eff0f40a66e85ab9=
dfb37681bf025ac4